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Storage Steps Up

what the battery at Notrees does. It delivers the exact amount of power that’s needed, when it’s needed, which is of tremendous value to the grid operator.

FPP How often have delivered power for frequency regulation?

Gates: In terms of the amount of capacity we were called to supply, I would say roughly six to 10 deployments per hour.

FPP It’s been reported that frequency regulation is the first bridgehead for energy storage. How else might the technology be employed?

Gates: We’ve done some dispatch into the ERCOT energy market during peak periods when prices are high. But the price differential usually isn’t high enough to do that on a regular basis. During the cold snap in January, 2014, spot prices were in the thousands of dollars, so it certainly made sense to take advantage of that.

Other opportunities exist but they’re market specific.. For example, in California, they have a tremendous need for assets that can ramp quickly and are very flexible, given the increasing penetration of renewables. Most markets haven’t kept up with what storage can provide because they’re designed for conventional generation.

It’s like comparing the smart phone to wall-mounted phones we used 20 years ago. First we went from a phone tethered to the wall to one that was cordless. When the smart phone came along, it could make phone calls, but it could also do all kinds of things nobody ever contemplated- surf[MTF1]  the web, send text or email messages, download music, take photos, play games and provide navigation assistance.

That’s where we’re heading with storage. To use storage only for what conventional generators do doesn’t tap its true value.

FPP And what is its true value?

Gates: Flexibility and reliability are probably the two biggest values. Storage is very flexible in terms of ramp control, and that’s a big issue in California right now. In California, you have a huge amount of PV coming on all at once as the sun comes up in the morning. So you have to ramp down the conventional generation that’s been on-line overnight. And at the end of the day, as the PV generation starts to fall off, you have to transition from PV back to conventional generation. Storage is ideally suited to support that morning-evening transition.

Further, a 100-MW storage unit can provide 100 MW of generation and 100 MW of load. When PV comes on in morning, the energy needed to charge storage generates 100 MW of load, while also providing 100 MW of generation as the sun falls off in the evening. So in effect you have a 100-MW storage unit providing 200 MW of grid flexibility.

Now, compare that to a gas turbine. A 100-MW combustion turbine has to maintain a minimum output of 50 MW, for example – its minimum set point – to be synchronized to the grid. Depending on how you look at it, you either get two or four times the grid flexibility for the same nameplate megawatts when using storage instead.

Another benefit is siting flexibility. You can place

Could grid-integrated batteries change the way power producers operate fossil power plants?
Could grid-integrated batteries change the way power producers operate fossil power plants?
Intro Text: 
Could batteries affect the way power producers evaluate and operate their generating assets – in particular fossil fired generating assets they currently use to supply ancillary services? Duke Energy's Jeff Gates talks about the Notrees project and the future of battery storage.
Publishing Date: 
Tuesday, February 25, 2014 (All day)